title: The effect of accelerated ageing on colour stability of visible light-cured (VLC) chairside denture liners.
abstract: OBJECTIVE
  The purpose of this study was to assess the colour stability of seven visible light-cured (VLC) hard and soft denture liners by an in vitro accelerated ageing test and compare them with two autopolymerised hard and soft liners.
  
  
  METHODS
  Ten specimens of each material were fabricated. The initial colour was measured with a tri-stimulus colorimeter. One set of five specimens was placed in distilled water at 37°C in the dark for 15 days, while the remaining were subjected to UV/visible light-accelerated ageing initially for 24 h and then for 144 h. Colour change (ΔΕ) was calculated. Data were statistically analysed by anova, Tukey and t-tests at α = 0.05.
  
  
  RESULTS
  All the liners showed clinically acceptable colour change (ΔΕ ≤ 6.8) in distilled water. The colour changes after ageing for Triad DuaLine, Lightdon U, Ufi Gel H and Light Liner Hard were clinically unacceptable (ΔΕ ≥ 6.8), whereas LightLiner Soft, Astron LC Soft, Triad Resiline and Flexacryl Soft presented slighter and clinically acceptable colour change (ΔΕ ≤ 6.8).
  
  
  CONCLUSIONS
  Accelerated ageing affected significantly the colour stability of all denture liners tested except Astron LC Soft. Soft VLC denture liners were more colour-stable than hard VLC liners.
authors.affiliation: Department of Prosthodontics, Dental School, University of Athens, Athens, Greece. jkostoul@dent.uoa.gr
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kostoulas
authors.forename: Gregory
authors.initials: G
authors.lastname: Polyzois
authors.forename: Anastasios
authors.initials: A
authors.lastname: Mitsoudis
authors.forename: Victoria
authors.initials: V
authors.lastname: Kavoura
authors.forename: Maria
authors.initials: M
authors.lastname: Frangou
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry / Q000528:radiation effects; D003116:Color; D003124:Colorimetry / Q000295:instrumentation; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D003822:Denture Liners; D006244:Hardness; D006801:Humans; D008027:Light; D008422:Materials Testing; D012826:Silicone Elastomers / Q000737:chemistry / Q000528:radiation effects; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; C078088:Astron LC; D003764:Dental Materials; D012826:Silicone Elastomers; C483158:Ufi gel; D014867:Water; C060386:Triad resin